Download or read book Assessing the Ecohydrologic Consequences of Woody Plant Encroachment written by and published by . This book was released on 2009 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: This three part study attempted to enhance our understanding of vegetation change and its potential effects on ecohydrology in drylands. The first study developed a method to measure the velocity of shallow overland flow. Under rainfall simulation, dye tracers were applied to runoff and photographed to calculate mean surface velocity. Results showed this approach was a significant improvement explaining 13% more of the variation in mean velocity compared to traditional methods. Results from the first study were used to compare hydraulic parameters on shrub- and grass-dominated plots in the second study. Previous research has suggested microtopography in shrublands acts to concentrate flow, leading to increased runoff velocity compared to grasslands. However, present findings showed that flow velocities were similar on many grass and shrub plots; only plots with ground cover>90% exhibited significantly lower flow velocities, and some shrub-dominated plots had lower flow velocities than grass-dominated plots implying that horizontal water flux is reduced under certain states of woody plant encroachment. In terms of ground cover characteristics, velocity increased rapidly with increases in the fraction of bare soil, up to a value of 2̃0% bare soil. Above 2̃0% bare soil, basal gap became a dominant factor suggesting a possible threshold where spatial metrics related to the distance between plants become important indicator of shallow flow velocity. The third study tested an approach to quantify woody plant canopy metrics over large areas. Radar has been used to map biomass in forests but few studies have examined open canopy ecosystems. Field measurements of shrublands were compared to satellite images to identify the relationship between radar signal and height and cover of woody vegetation. Results indicated that radar signal increased positively with shrub height or shrub volume explaining 74% and 90% of the variation, respectively. The effect of surface roughness and sub-canopy species on radar signal appears reduced when images are collected at large incidence angles.
Download or read book Rangeland Systems written by David D. Briske and published by Springer. This book was released on 2017-04-12 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is open access under a CC BY-NC 2.5 license. This book provides an unprecedented synthesis of the current status of scientific and management knowledge regarding global rangelands and the major challenges that confront them. It has been organized around three major themes. The first summarizes the conceptual advances that have occurred in the rangeland profession. The second addresses the implications of these conceptual advances to management and policy. The third assesses several major challenges confronting global rangelands in the 21st century. This book will compliment applied range management textbooks by describing the conceptual foundation on which the rangeland profession is based. It has been written to be accessible to a broad audience, including ecosystem managers, educators, students and policy makers. The content is founded on the collective experience, knowledge and commitment of 80 authors who have worked in rangelands throughout the world. Their collective contributions indicate that a more comprehensive framework is necessary to address the complex challenges confronting global rangelands. Rangelands represent adaptive social-ecological systems, in which societal values, organizations and capacities are of equal importance to, and interact with, those of ecological processes. A more comprehensive framework for rangeland systems may enable management agencies, and educational, research and policy making organizations to more effectively assess complex problems and develop appropriate solutions.
Download or read book Exploring the Ecohydrological Impacts of Woody Plant Encroachment in Paired Watersheds of the Sonoran Desert Arizona written by Nicole A. Pierini and published by . This book was released on 2013 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Woody plant encroachment is a worldwide phenomenon linked to water availability in semiarid systems. Nevertheless, the implications of woody plant encroachment on the hydrologic cycle are poorly understood, especially at the catchment scale. This study takes place in a pair of small semiarid rangeland undergoing the encroachment of Prosopis velutina Woot., or velvet mesquite tree. The similarly-sized basins are in close proximity, leading to equivalent meteorological and soil conditions. One basin was treated for mesquite in 1974, while the other represents the encroachment process. A sensor network was installed to measure ecohydrological states and fluxes, including precipitation, runoff, soil moisture and evapotranspiration. Observations from June 1, 2011 through September 30, 2012 are presented to describe the seasonality and spatial variability of ecohydrological conditions during the North American Monsoon (NAM). Runoff observations are linked to historical changes in runoff production in each watershed. Observations indicate that the mesquite-treated basin generates more runoff pulses and greater runoff volume for small rainfall events, while the mesquite-encroached basin generates more runoff volume for large rainfall events. A distributed hydrologic model is applied to both basins to investigate the runoff threshold processes experienced during the NAM. Vegetation in the two basins is classified into grass, mesquite, or bare soil using high-resolution imagery. Model predictions are used to investigate the vegetation controls on soil moisture, evapotranspiration, and runoff generation. The distributed model shows that grass and mesquite sites retain the highest levels of soil moisture. The model also captures the runoff generation differences between the two watersheds that have been observed over the past decade. Generally, grass sites in the mesquite-treated basin have less plant interception and evapotranspiration, leading to higher soil moisture that supports greater runoff for small rainfall events. For large rainfall events, the mesquite-encroached basin produces greater runoff due to its higher fraction of bare soil. The results of this study show that a distributed hydrologic model can be used to explain runoff threshold processes linked to woody plant encroachment at the catchment-scale and provides useful interpretations for rangeland management in semiarid areas.
Download or read book Consequences of Woody Plant Encroachment for Mammalian Predators written by Virginia Ann Seamster and published by . This book was released on 2010 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ecological Implications of Livestock Herbivory in the West written by Martin Vavra and published by . This book was released on 1994 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Habitat Loss and Fragmentation Caused by Woody Plant Encroachment on Native Plant Diversity and on an Invasive Grass written by Karen Marie Alofs and published by . This book was released on 2010 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Habitat loss, habitat fragmentation and species invasions have been recognized as three of the leading threats to biodiversity. I examined the effects of habitat loss and fragmentation on native and invasive plants in central Texas. During the last century, the density and abundance of woody plants has been increasing in the savannas of eastern Edwards Plateau. This process, known as woody plant encroachment, not only reduces the amount of open herbaceous habitat but also fragments that habitat creating smaller and more isolated patches. In three studies, I investigated the consequences of this habitat loss and fragmentation for plants which do not occur under the cover of woody plants including native grasses and forbs and the invasive Eurasian bunchgrass, Bothriochloa ischaemum (King Ranch Bluestem). In the first study, I show that woody plant encroachment reduces native herbaceous species richness (the number of species in a given area). Using a collection of historical aerial photographs, I demonstrate that current native herbaceous species richness was most strongly related to recent habitat amount, but to the degree of habitat fragmentation at least 50 years ago. In a second study, I show that the presence of B. ischaemum was negatively related to the degree of fragmentation in the surrounding landscape. Finally, I found that B. ischaemum had higher rates of germination and growth in experimental plots where the species commonly lost with woody plant encroachment were removed than in unmanipulated control plots. Together, this work suggests that woody plant encroachment is directly slowing the spread of an invasive species while indirectly facilitating its establishment.
Download or read book Wild Rangelands written by Johan T. du Toit and published by John Wiley & Sons. This book was released on 2012-11-06 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rangeland ecosystems which include unimproved grasslands,shrublands, savannas and semi-deserts, support half of theworld’s livestock, while also providing habitats for some ofthe most charismatic of wildlife species. This book examines thepressures on rangeland ecosystems worldwide from human land use,over-hunting, and subsistence and commercial farming of livestockand crops. Leading experts have pooled their experiences from allcontinents to cover the ecological, sociological, political,veterinary, and economic aspects of rangeland management today. This book provides practitioners and students ofrangeland management and wildland conservation with a diversity ofperspectives on a central question: can rangelands be wildlands? The first book to examine rangelands from a conservationperspective Emphasizes the balance between the needs of people andlivestock, and wildlife Written by an international team of experts covering allgeographical regions Examines ecological, sociological, political, veterinary, andeconomic aspects of rangeland management and wildland conservation,providing a diversity of perspectives not seen before in a singlevolume
Download or read book Savanna Woody Plants and Large Herbivores written by Peter Frank Scogings and published by John Wiley & Sons. This book was released on 2019-09-30 with total page 794 pages. Available in PDF, EPUB and Kindle. Book excerpt: Insights on current research and recent developments in understanding global savanna systems Increasingly recognized as synonymous with tropical grassy biomes, savannas are found in tropical and sub-tropical climates as well as warm, temperate regions of North America. Savanna Woody Plants and Large Herbivores examines the interactions between woody plants and browsing mammals in global savannas—focusing primarily on the C4 grassy ecosystems with woody components that constitute the majority of global savannas—and discusses contemporary savanna management models and applications. This much-needed addition to current research examines topics including the varying behavior of browsing mammals, the response to browsing by woody species, and the factors that inhibit forage intake. Contributions from an international team of active researchers and experts compare and contrast different savanna ecosystems, offering a global perspective on savanna functioning, the roles of soil and climate in resource availability and organism interaction, and the possible impacts of climate change across global savannas. Fills a gap in literature on savanna management issues, including biodiversity conservation and animal production Applies concepts developed in other biomes to future savanna research Complements contemporary books on savanna or large herbivore ecology Focuses on the woody component of savanna ecosystems and large herbivore interactions in savannas Compares tree-mammal systems of savannas and other eco-systems of temperate and boreal regions Provides numerous case studies of plant-mammal interactions from various savanna ecosystems Savanna Woody Plants and Large Herbivores is a valuable addition to those in fields such as ecology, wildlife and conservation biology, natural resource management, and environmental science.
Download or read book Ecohydrologic Dynamics and Social Impacts of Western Juniper in Snow dominated Sagebrush Steppe written by Ryan J. Niemeyer and published by . This book was released on 2015 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semi-arid social-ecological systems in the western U.S. have undergone drastic changes due to grazing, woody plant encroachment, and urbanization. Specifically in the northern Great Basin, western juniper (Juniperus occidentalis) has increased in cover by 10-fold over the last 140 years. These changes can alter both hydrologic and social characteristics of the social-ecological system. To understand these impacts, we studied both the hydrologic and the social-ecological impacts of western juniper encroachment in the sagebrush-steppe. The hydrologic and social research was carried out in the Owyhees of southwestern Idaho. The objective of the hydrologic research was to understand how western juniper influenced both above and below ground hydrologic processes. The objective of the social science research was to develop a social-ecological impact assessment that better addressed both the social and ecological aspects of impact assessments required by the National Environmental Policy Act. The hydrologic research included field work conducted at Reynolds Creek Experimental Watershed in the Owyhee Mountains and simulations of future climate. This research revealed that juniper not only intercept a large portion of rain and snow, but due to tree wells that form below trees, cause change in below-canopy snow topography that increases snow deposition below trees. Future climate simulations revealed that while climate primarily fixes the timing of above-ground hydrologic processes (i.e. peak snowpack, surface water input, etc.), changes in land cover have a greater impact on the amount of these fluxes. The below-ground research revealed that western juniper preferentially funnel infiltration at their base, likely due to a combination of roots providing preferential flowpaths and hydrophobic soils concentrating infiltration. Electrical resistivity tomography surveys revealed large juniper can extract moisture in the saprolite and weathered bedrock - as deep as 10 m below the surface. The social science research included five workshops and revealed that a deliberative social-ecological assessment process can reveal impacts not otherwise captured with other technical or survey methods.
Download or read book Climate Vulnerability written by and published by Elsevier. This book was released on 2013-03-15 with total page 1086 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate change has been the subject of thousands of books and magazines, scientific journals, and newspaper articles daily. It’s a subject that can be very political and emotional, often blurring the lines between fact and fiction. The vast majority of research, studies, projections and recommendations tend to focus on the human influence on climate change and global warming as the result of CO2 emissions, often to the exclusion of other threats that include population growth and the stress placed on energy sources due to emerging global affluence. Climate Vulnerability, Five Volume Set seeks to strip away the politics and emotion that surround climate change and will assess the broad range of threats using the bottom up approach—including CO2 emissions, population growth, emerging affluence, and many others—to our five most critical resources: water, food, ecosystems, energy, and human health. Inclusively determining what these threats are while seeking preventive measures and adaptations is at the heart of this unique reference work. Takes a Bottom-Up approach, addressing climate change and the threat to our key resources at the local level first and globally second, providing a more accurate and inclusive approach. Includes extensive cross-referencing, which is key to readers as new connections between factors can be discovered. Cuts across a number of disciplines and will appeal to Biological Science, Earth & Environmental Science, Ecology, and Social Science, comprehensively addressing climate change and other threats to our key resources from multiple perspectives
Download or read book Hydroecology and Ecohydrology written by Paul J. Wood and published by John Wiley & Sons. This book was released on 2008-02-28 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: This state-of-the-art, research level text considers the growing volume of research at the interface of hydrology and ecology and focuses on: the evolution of hydroecology / ecohydrology process understanding hydroecological interactions, dynamics and linkages methodological approaches detailed case studies future research needs The editors and contributors are internationally recognised experts in hydrology and ecology from institutions across North America, South America, Australia, and Europe. Chapters provide a broad geographical coverage and bridge the traditional subject divide between hydrology and ecology. The book considers a range of organisms (plants, invertebrates and fish), provides a long-term perspective on contemporary and palaeo-systems, and emphasises wider research implications with respect to environmental and water resource management. Hydroecology and Ecohydrology is an indispensable resource for academics and postgraduate researchers in departments of physical geography, earth sciences, environmental science, environmental management, civil engineering, water resource management, biology, zoology, botany and ecology. It is also of interest to professionals working within environmental consultancies, organizations and national agencies.
Download or read book Three Techniques for Assessing Herbicide Effects on Woody Plants written by Paul Willard Perry and published by . This book was released on 1964 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modelling Soil Erosion by Water written by John Boardman and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: TO THE MODEL EVALUATION 1. MODELLING SOIL EROSION BY WATER l 2 John Boardman and David Favis-Mortlock 1 School of Geography and Environmental Change Unit Mansfield Road University of Oxford Oxford OX1 3TB UK 2 Environmental Change Unit University of Oxford 5 South Parks Road Oxford OX1 3UB UK Introduction This volume is the Proceedings of the NATO Advanced Research Workshop 'Global Change: Modelling Soil Erosion by Water', which was held on II-14th September 1995, at the University of Oxford, UK. The meeting was also one of a series organised by the IGBP 1 GCTE Soil Erosion Network, which is a component of GCTE's Land Degradation Task (3.3.2) (Ingram et aI., 1996; Valentin, this volume). One aim of the GCTE Soil Erosion Network is to evaluate the suitability of existing soil erosion models for predicting the possible impacts of global change upon soil erosion. Due to the wide range of erosion models currently, in use or under development, it was decided to evaluate models in the following sequence Favis-Mortlock et al., 1996): • field-scale water erosion models • catchmenr-scale water erosion models • wind erosion models • models with a landscape-scale and larger focus. As part of this strategy, the first stage of the GCTE validation of field-scale erosion models was carried out at the Oxford NATO-ARW. I A list of Acronyms fonns Appendix A.
Download or read book Western North American Juniperus Communities written by Oscar van Auken and published by Springer Science & Business Media. This book was released on 2007-12-04 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: In North America, Juniperus woodlands occupy approximately 55 million hectares, an area larger than the state of Texas. This title addresses various aspects of the biology, ecology, and management of Juniperus woodlands and savannas, synthesizing past and current research findings as well as proposed research. The book provides ecologists, land managers, and foresters with a solid foundation in Juniperus ecosystems, enabling them to manage the communities for maximum sustained productivity and diversity.
Download or read book Woody Plants and Forest Ecosystems in a Complex World Ecological Interactions and Physiological Functioning Above and Below Ground written by Boris Rewald and published by Frontiers Media SA. This book was released on 2020-04-01 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geomorphology in the Anthropocene written by Andrew S. Goudie and published by Cambridge University Press. This book was released on 2016-10-10 with total page 335 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Anthropocene is a major new concept in the Earth sciences and this book examines the effects on geomorphology within this period. Drawing examples from many different global environments, this comprehensive volume demonstrates that human impact on landforms and land-forming processes is profound, due to various driving forces, including: use of fire; extinction of fauna; development of agriculture, urbanisation, and globalisation; and new methods of harnessing energy. The book explores the ways in which future climate change due to anthropogenic causes may further magnify effects on geomorphology, with respect to future hazards such as floods and landslides, the state of the cryosphere, and sea level. The book concludes with a consideration of the ways in which landforms are now being managed and protected. Covering all major aspects of geomorphology, this book is ideal for undergraduate and graduate students studying geomorphology, environmental science and physical geography, and for all researchers of geomorphology.
Download or read book Grasslands of the World written by Food and Agriculture Organization of the United Nations and published by Food & Agriculture Org.. This book was released on 2005 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together information on the contrasting characteristics, condition, present use and problems of the world's main natural grasslands. Since grassland is commercialized through the grazing animal, particular attention is paid to the livestock production systems associated with each main type. Grazing resources are more than simply edible herbage: many other factors have to be taken into account, notably water in all areas, and shelter in winter-cold climates. Seasonality of forage supply is a characteristic of almost all grazing lands, so the strategies for dealing with lean seasons are described. The main problems of each type are mentioned and possible strategies for their sustainable management discussed - taking into account their multiple functions, not only livestock production. The book is primarily aimed at agricultural scientists, educationalists, extensionists and decision-makers with interests in responsible use of extensive grasslands.
